The relationship of dietary fish intake to level of pulmonary function in the first National Health and Nutrition Survey (NHANES I)

Eicosapentaenoic acid (EPA), which predominates in marine fish, tends to counteract and inhibit the uptake and incorporation of arachidonic acid and membrane phospholipids and dilute arachidonic acid as a potential substrate for oxidation. Thus, fish intake may be protective for the occurrence of asthma and other pulmonary diseases. We wanted to examine the relationship between the effect of chronic dietary intake to fish and its relationship to level of pulmonary function. We performed this analysis using data from the First National Health and Nutritional Examination Survey (NHANES I). A detailed subsample of 2,526 adults had a medical history questionnaire, that included a 24-hour dietary recall, and performed spirometric examination. Log of forced expiratory volume in one second (FEV1) served as a dependent variable in regression analysis which included an adjustment for height, age, cigarette smoking and gender. When added to the regression model including the above variables dietary fish intake showed a protective association with FEV1 (beta = 0.008 +/- 0.004, p = 0.028). When smokers were excluded from the analysis, the effect of fish intake on pulmonary function appeared to increase slightly (beta = 0.0108 +/- 0.006, p = 0.61). These data suggest that chronic dietary intake of fish is associated with higher levels of pulmonary function and is consistent with the hypothesis of an effect of fish oil on arachidonic acid metabolism.